Cooled microwave denervation catheter configuration

ABSTRACT

A cooled microwave denervation catheter includes a catheter body having at least one fluid passage and an interior lumen therein, a balloon in communication with the at least one fluid passage to receive cooling fluid to inflate the balloon, and a microwave antenna catheter configured to be inserted into the interior lumen of the catheter body. The microwave antenna catheter has a distal end configured to engage a taper of the interior lumen, thereby positioning the microwave antenna in a desired location of the interior lumen.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.61/931,420 filed Jan. 24, 2014 for “Cooled Microwave DenervationCatheter Configuration” by E. Rudie et al., which is incorporated byreference herein in its entirety.

BACKGROUND

The present disclosure is directed to catheter configurations for cooledmicrowave denervation.

SUMMARY

A cooled microwave denervation catheter includes a catheter body havingat least one fluid passage and an interior lumen therein, the interiorlumen having a first portion in a first axial region, a second portionin a second axial region, and a taper between the first portion and thesecond portion, the second portion having a smaller diameter than thefirst portion. A balloon communicates with the at least one fluidpassage to receive cooling fluid for inflating the balloon into a shapethat surrounds the catheter body at the first portion of the interiorlumen, the cooling fluid having a temperature that is less than basalbody temperature. A microwave antenna catheter is configured to beinserted into the interior lumen of the catheter body, the microwaveantenna catheter including a coaxial cable and a microwave antennaconnectable to a microwave generator to supply power to the microwaveantenna to cause microwave energy to be emitted from the microwaveantenna. A distal end of the microwave antenna catheter is configured toengage the taper between the first portion and the second portion of thecatheter body upon insertion into the interior lumen, therebypositioning the microwave antenna in the first portion of the interiorlumen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cooled microwave denervation catheter embodimentwherein the treatment catheter is separated into a first catheter and anantenna catheter.

FIG. 2 is an enlarged view of the distal end of the first catheter shownin FIG. 1.

FIG. 3 is an enlarged view of the distal end of the first catheter shownin FIG. 1, with the antenna catheter positioned within a lumen andadvanced until the distal end of the antenna catheter engages a taper.

FIG. 4 is an enlarged and shaded view of the distal end of the firstcatheter shown in FIG. 1, with the antenna catheter placed within thefirst catheter.

FIG. 5 is an enlarged cross section of the middle section of the firstcatheter shown in FIG. 1.

FIG. 6 is an enlarged cross section of a portion of the middle sectionof the first catheter shown in FIG. 1.

FIG. 7 is an enlarged cross section of the distal end of the firstcatheter shown in FIG. 1.

FIG. 8 depicts another cooled microwave denervation catheter embodimentin which the treatment catheter is separated into a first catheter and asecond catheter.

FIG. 9 depicts the distal portion of the first catheter shown in FIG. 8with the second catheter placed within it.

FIG. 10 is another view of the distal end of the first catheter shown inFIG. 8.

FIG. 11 is a cross section of multi lumen tubing showing cooling lumensand also a guide wire/antenna cable lumen.

FIG. 12 is a shaded drawing of the distal end of the first cathetershown in FIG. 8.

FIG. 13 depicts alternate cooled microwave denervation catheter shaftembodiments that can be used in conjunction with any embodiment thatrequires an antenna cable lumen, inflow cooling fluid lumen, outflowcooling fluid lumen, and a guide wire lumen or a subset of these.

FIG. 14 depicts a cooled microwave denervation catheter embodiment inwhich two balloons are used to occlude the body lumen, center theantenna within the body lumen, and create a chamber within which coolantis circulated.

FIG. 15 depicts a cooled microwave denervation catheter embodiment inwhich a guide catheter is equipped with an occluding/locating ballooninflated through a port via a lumen within a multi lumen tube, to locateguide catheter just proximal to a treatment site adjacent to the bodylumen.

FIG. 16 depicts a dual balloon cooled microwave denervation catheterembodiment wherein the treatment catheter includes a microwave antennamounted within a balloon.

FIG. 17 is another view of the catheter shown in FIG. 16.

FIG. 18A and FIG. 18B are alternate views of the catheter shown in FIG.16.

FIG. 19 depicts the distal end of another embodiment of a cooledmicrowave denervation catheter.

FIG. 20 depicts the distal end of a further embodiment of a cooledmicrowave denervation catheter.

FIGS. 21-23 depict a dual catheter embodiment of a cooled microwavedenervation catheter similar to that depicted in FIG. 8.

FIG. 24 depicts an alternate cross section for the shaft of the cathetershown in FIGS. 21-23.

DETAILED DESCRIPTION

The present disclosure is directed to catheter configurations for cooledmicrowave denervation. In certain embodiments, denervation is performedby positioning a catheter carrying a microwave antenna within a bodyvessel/lumen adjacent targeted nerves being treated, circulating coolingfluid around the microwave antenna in thermal contact with the innerwall of the body vessel/lumen, supplying power to the microwave antennato cause microwave energy to be emitted from the microwave antennatoward the targeted nerves. The power supplied to the microwave antennaand the cooling fluid circulated around the microwave antenna arecontrolled to cause the targeted nerves to be heated to a temperaturesufficient to cause thermal damage while the wall of the bodyvessel/lumen is maintained at a temperature where thermal damage doesnot occur. Various embodiments of cooled microwave denervation catheterconfigurations are described herein and shown in FIGS. 1-24.

FIG. 1 depicts an embodiment wherein the treatment catheter is separatedinto two catheters. The first catheter 10 has distal end 12, middleportion 14 and proximal end 16. Distal end 12 includes cooling balloon20 adapted to communicate with lumens for inflow and outflow. The lumensexit the catheter through inlet connector 22 and outlet connector 24 onmanifold 30. Catheter 10 also contains lumen 44 (shown in FIG. 2)extending from tip port 26 to proximal port 28 on manifold 30 throughwhich a guide wire or antenna catheter 50 may be inserted. The secondcatheter, antenna catheter 50, contains microwave antenna 56 connectedthrough coaxial cable 58 to a suitable connector, 60, such as asubminiature version A (SMA) connector, connected on the proximal end 54of antenna catheter 50. Antenna 56 may be any embodiment as described inU.S. application Ser. No. 14/032,013 filed Sep. 19, 2013, which ishereby incorporated by reference.

FIG. 2 is an enlarged view of distal end 12 of catheter 10. Inner tubemember 32 forms lumen 44 within which antenna catheter 50 or a guidewire may be inserted. Taper 40 serves to transition the diameter oflumen 44 to match tip orifice 26. Taper 40 also serves to align antennacatheter 50 correctly within cooling balloon 20. A cooling lumen 37(shown in FIGS. 5 and 6) is formed in the annular space between tubemember 32 and tube member 34. Coolant flows into lumen 37 and exits intoballoon 20 through proximal exchange port 35 formed when outer tubemember 38 ends. Inner tube member 34 extends to the distal end ofballoon 20 and forms distal coolant exchange port 39 into which coolantflows and into lumen 36 formed by the annular space between inner andouter tube member. Distal exchange port 39 is located near the distalend of balloon 20 to ensure that coolant is circulated withinsubstantially the entire length of cooling balloon 20. Tube member 38serves as the outer wall of catheter 10 and forms a cooling lumen in theannular space between tube member 34 and tube member 38. Radio opaquemarkers 46 are positioned about tube member 34 and are used tofacilitate location of catheter 10 within renal artery underfluoroscopic guidance.

FIG. 3 is an enlarged view of distal end 12 of catheter 10 with antennacatheter 50 positioned within lumen 44 and advanced until distal end 52of antenna catheter 50 engages taper 40. Antenna 56 is shown correctlypositioned within balloon 20.

FIG. 4 is an enlarged and shaded view of distal end 12 of catheter 10with antenna catheter 50 placed within catheter 10. Shading of balloon20 and catheter tubing helps to visualize the tubing walls.

FIG. 5 is an enlarged cross section of the middle section 14 of catheter10. Coolant flows in the annular spaces 37 and 36 between tube members32, 34 and 38. The inner lumen 44, central to tube member 32, maycontain guide wire 70 to facilitate introduction, or antenna catheter 50for treatment. The guide wire 70 and antenna catheter 50 are eachrepresented by the same circular cross section. However, they may be ofdifferent diameters and only one of them will be present at a time.

FIG. 6 is an enlarged cross section of the middle of section 14 ofcatheter 10. However, this drawing has inner lumen 44 empty. Centrallumen 44, tubing members 32, 34 and 38 and annular space 37 and 36 arethe same as in FIG. 5.

FIG. 7 is an enlarged cross section of distal end 12 of catheter 10.Radio opaque markers 46 are more clearly visible within balloon 20 andare used to guide location of balloon 20 within the treatment location.

In an exemplary operation of the embodiment represented in FIGS. 1-7,catheter 10 is advanced over a guide wire 70 to the desired treatmentlocation. Radio opaque marker bands 46 help the operator position thecooling balloon catheter 10 in the desired location via fluoroscopy. Theguide wire 70 is then removed, leaving the cooling balloon catheter 10in place. The antenna catheter 50 is then inserted into the centrallumen 44 of catheter 10 and advanced until distal end 52 of microwavecatheter 50 engages taper 40 and thereby locates antenna 56 withinballoon 20 in order to precisely target the treatment location.Denervation treatment is then executed by applying coolant flow andmicrowave power in accordance with the U.S. application Ser. No.14/032,013 referenced above. Once the treatment period is complete,coolant is discontinued, balloon 20 is deflated, and both the coolingballoon catheter 10 and microwave catheter 50 are removed.

It can be appreciated that one advantage of this embodiment is that thenumber of lumens required to perform the treatment is reduced. This is aresult of the guide wire 70 and antenna catheter 50 sharing the samelumen at different times during the procedure. Additionally, the lumensize available to the guide wire is much larger. Typical guide wirediameters for vascular interventions may be 0.014″, 0.018″, 0.035″ and0.038″. Since the diameter of the antenna catheter 10 in a preferredembodiment is greater than 0.038″, central lumen 44 may in someembodiments accommodate guide wire sizes as large as 0.038. These largerguide wire sizes can be an advantage in providing support to thedelivery of the cooling balloon catheter in comparison with the use of0.014″ or 0.018″ guidewires.

Embodiment DNX-001 B

FIG. 8 depicts another embodiment in which the treatment catheter isseparated into two catheters. The first catheter 110 is a coolingballoon catheter that contains a microwave antenna within the coolingballoon 120 in the distal portion 112. Connection manifold 130 islocated on proximal portion 116 of catheter 110. Cooling connections 122and 124 communicate through manifold 130 to cooling lumens withincatheter 110 to the distal section 112. A guide wire may be insertedinto orifice 128 and advanced through catheter 110, exiting orifice attip 126 to facilitate placement of catheter 110 within a body at thedesired treatment location.

Once catheter 110 is in the desired location, the guide wire may beremoved and catheter 150 may be inserted into orifice 128. Catheter 150contains coaxial cable 158 extending from contacts 159 located at distalportion 152 to microwave connector 160. Microwave connector 160 may bean SMA or other appropriate connector. Once catheter 150 is properlypositioned within catheter 110, contacts 159 on catheter 150 mate withcorresponding contacts 157 (shown in FIG. 9) located within catheter 110to enable microwave excitation of antenna 156 (FIG. 9). Coolant may becirculated through lumens within 110 so that balloon 120 may be inflatedand denervation treatment may commence. Once the treatment period iscomplete the cooling balloon with antenna and coaxial cable are removed.

FIG. 9 depicts distal portion 112 of catheter 110 with catheter 150placed within. Antenna 156 is located within balloon 120 and iselectrically connected to catheter 150 by contacts 157 and 159 to enableit to be energized by microwave current applied to connector 160 (FIG.8) located on the proximal end of catheter 150. Coolant is circulatedthrough manifold 130, lumens 136 and 137 and into balloon 120 throughproximal and distal ports 135 and 139. Balloon 120 is inflated by thiscirculating coolant so that the body lumen containing treatment catheter110 may be protected. With catheter 150 placed within catheter 110 andconnected as described, denervation treatment may commence. Once thetreatment period is complete the cooling balloon with antenna andcoaxial cable are removed. Radio opaque marker bands may be used to helpvisualize location of balloon 120 within the body lumen adjacent to theregion requiring treatment.

FIG. 10 is another view of distal end 112 of catheter 110. Antenna 156is clearly located on multi lumen tube 138 (shown in cross-section inFIG. 11). Proximal and distal coolant ports 135 and 139 are more clearlyvisible as apertures in multi lumen tube 138 that enable communicationwith lumens 136 and 137 (FIG. 11). Radio opaque marker bands may be usedto help visualize location of balloon 120 within the body lumen adjacentto the region requiring treatment.

FIG. 11 is a cross section of multi lumen tubing 138 showing coolinglumens 136 and 137 and also guide wire/antenna cable lumen 144.

FIG. 12 is a shaded drawing of distal end 112 of catheter 110. Thelocation of antenna 156, and cooling ports 135 and 139 are visible.

In some embodiments, for optimal microwave energy transmission it may bedesirable for the diameter of the microwave antenna to be significantlylarger than the commonly used 0.035″ or 0.038″ guidewires. Mounting thislarger antenna inside the balloon allows the lumen for guidewire andcoaxial cable to be suited for 0.035″ or 0.038″ guidewire. Marker bandsmay not be necessary in this embodiment if the antenna is significantlyradiopaque.

Shaft Embodiments

FIG. 13 depicts alternate shaft embodiments that can be used inconjunction with any embodiment that requires an antenna cable lumen245, inflow cooling fluid lumen 236, outflow cooling fluid lumen 237,and a guide wire lumen 244 or a subset of these.

Embodiment DNX-005

FIG. 14 depicts an embodiment in which two balloons are used to occludethe body lumen, center the antenna within the body lumen, and create achamber within which coolant is circulated. The catheter of thisembodiment is advanced over guide wire 370 exiting the device at orifice326 until proper position within the body lumen is achieved. Distalocclusion balloon 320 is attached to multi lumen tube 332 and isinflated through port 357. Proximal occlusion balloon 321 is attached toouter multi lumen tube 334 and is inflated through port 359. Bothballoons center antenna 356 within chamber 361 formed by occludingballoons 320 and 321. Coolant is circulated through lumens within multilumen tube 334 and enters chamber 361 through port 339. Coolant exitschamber 361 through port 335 and returns through lumens within multilumen tube 334. Cooling of the body lumen is accomplished by direct heatexchange between coolant within chamber 361 and the body lumen.Microwave antenna 356 may then be energized to accomplish denervation.

Embodiment DNX-007

FIG. 15 depicts an embodiment in which guide catheter 472 is equippedwith occluding/locating balloon 421 inflated through port 459 via alumen within multi lumen tube 434, to locate guide catheter justproximal to a treatment site adjacent to the body lumen. Antennacatheter 450 is advanced over guide wire 470 exiting an orifice at tip426, through guide catheter 472, until it is positioned within the bodylumen at the treatment site. Proximal balloon 420 is inflated throughport 457 via a lumen within multi lumen tube 432 and thereby centersantenna 456 within chamber 461 formed by balloons 420 and 421. Coolantmay then be circulated through a lumen within multi lumen tube 432,through distal coolant port 439 and into chamber 461. The body lumen iscooled by direct contact with coolant along chamber 461. Coolant entersport 435 formed by the annular space between catheter 450 and the innerlumen of guide catheter 472. Since the cooling fluid is returned thruthe guide catheter lumen by entering orifice 435 formed by the guidecatheter inner lumen and the antenna catheter 450 outer shaft; catheter450 does not require an outflow lumen. Therefore, the available crosssectional area of 450 may be allocated to a single, higher flow lumen.

In operation, the guide catheter 472 is first positioned just proximalto the treatment site using standard interventional techniques. Once theguide catheter is in position, the balloon 421 on the guide catheter canbe inflated via port 459 to occlude the body lumen. This balloon canalso help anchor the guide catheter in the body lumen for the entireprocedure. Next, treatment catheter 450 is advanced through guidecatheter 472 and into the desired body lumen to the desired treatmentlocation. Distal balloon 420 may then be inflated via port 457. Coolantcirculation may then be initiated, thus circulating coolant withinchamber 461 from distal port 439 to proximal port 435 formed by theannulus between the outer shaft of 450 and the inner lumen of guidecatheter 472. Cooling fluid will make direct contact with artery wallfor optimal heat transfer effect.

Embodiment DNX-008

FIG. 16 depicts a dual balloon embodiment wherein the treatment catheter550 includes microwave antenna 556 mounted within balloon 520. A secondballoon 521 is mounted on guide catheter 572. On the proximal taper ofthe treatment catheter balloon 520 are apertures 535, which are smallenough to allow the balloon to inflate during the treatment period butlarge enough to allow cooling fluid to leak therethrough under pressure.Accordingly, coolant enters balloon 521 through distal port 539 intoballoon 520 where it circulates and cools the body lumen. Coolant exitsballoon 520 through apertures 535 at the proximal taper and flows intochamber 561 formed by balloons 520 and 521. Coolant enters port 574formed by the annular space between the outer shaft of catheter 550 andthe inner lumen of guide catheter 572 where it is captured externally.Coolant balloon 520 also centers antenna 556 within the body lumenadjacent to the region be treated.

In operation, guide catheter 571 is first positioned in the body lumenusing standard interventional techniques. Once the guide catheter is inposition, balloon 521 is inflated via port 559 to locate the guidecatheter and occlude the body lumen. Next, treatment catheter 550 isadvanced through the guide catheter 572 into the body lumen and to thedesired treatment location. Once there, balloon 520, is inflated bycirculating cooling fluid as described above. Antenna 556 is thenenergized as described in U.S. application Ser. No. 14/032,013. Oncetreatment is finished, balloon 520 is deflated by discontinuing coolantcirculation. Balloon 521 may then be deflated and catheter 550 and guidewire 572 may be repositioned to an additional treatment site or removed.

FIG. 17 is another view of catheter 550. Antenna 556 is mounted oncatheter shaft 532 within balloon 520. Apertures on catheter shaft 532form distal cooling port 539 that permits coolant to flow from thecooling lumen within shaft 523 and into balloon 520. Proximal coolingport 535 allows coolant to flow out of balloon 520. Orifice 526 locatedon distal tip of shaft 532 allows the guide wire to exit catheter 550.Radio opaque markers may be utilized if needed.

Embodiment DNX-008 B

FIG. 18A and FIG. 18B are alternate views of catheter 550. Catheter 550may be placed into the desired body lumen using only guide wire guidancethrough port at distal tip 526, or it may be placed with a standard,single lumen guide catheter, or a combination of both. In this case,coolant exits port 535 formed by many small apertures sized to maintainballoon pressure under active coolant flow, and flows directly into thebody lumen. The coolant flow rate and treatment duration are such that arelatively modest amount of coolant is discharged into the body lumen ofthe patient and is not harmful. This embodiment is similar to DNX-008described above, but does not include a balloon on the distal end of theguide catheter. In the case of the body lumen being an artery or vein,cooling fluid will be discharged into the blood stream of the patient. Ablood compatible fluid like sterile dextrose may be used in someembodiments.

Embodiment DNX-008 C

FIG. 19 depicts distal end of catheter 650. Balloon 620 functions asgenerally described in the preceding embodiments, except that apertures635 in balloon 620 serve to discharge cooling fluid into the body lumenon the distal side of balloon 620. Depending on the body lumen beingtreated, it may be preferable to discharge cooling fluid either proximalor distal to cooling balloon 620. A coolant port may be located in thedistal end of balloon 620 so that coolant along body lumen is optimallymoving in order that cooling may be most effectively accomplished.

Embodiment DNX-008 D

FIG. 20 depicts distal end of catheter 750. Balloon 720 functions asgenerally described in the preceding embodiments, except apertures 735in balloon 720 serve to discharge coolant both proximal and distal toballoon 720. Depending on the body lumen being treated, it may bepreferable to discharge a smaller volume of fluid on each side ofinflated balloon 720. In this case, a coolant port may be located in thecenter of the balloon or in another location to optimize cooling flowadjacent the body lumen being cooled.

Embodiment DNX-012

FIGS. 21, 22, and 23 depict a dual catheter embodiment similar to thatdepicted in FIG. 8. Cooling balloon/antenna catheter 810 includescentral lumen 844 through which either a guide catheter or a coaxialcable catheter exits orifice 826 at the tip. Coaxial cable catheter 850is initially separate from cooling balloon catheter 810, so thatcatheter 810 may be placed over a guide wire and positioned within bodylumen adjacent the desired denervation site. Once placed, the guide wireis removed and coaxial cable catheter 850 is advanced within lumen 844in catheter 810 so that contacts 859 on coaxial cable catheter engagewith mating contacts, 857 within catheter 810. Coolant flows through arelatively large lumen 836 into balloon 820 through orifice 839 and intothe interior of balloon 820. Coolant exits balloon 820 through apertures835 on the proximal taper of the balloon and is discharged into bodylumen as described above in previous embodiments.

Radio opaque markers 846 may be incorporated if helpful for placement.

As can be appreciated, apertures 835 on balloon 820 may be located onthe proximal taper as shown in FIG. 22, on the distal taper like thoseshown in FIG. 19, or on both proximal and distal tapers as shown in FIG.20. Alternately, the discharge holes may be located on the cylindricalwall of balloon 820. Coolant port 839 may be moved within balloon inorder to ensure that coolant is moving along body lumen contact area sothat cooling may be accomplished.

FIG. 24 depicts an alternate cross section for the shaft of catheter810. In this figure, as in FIG. 23, the outer tubing wall is identifiedas 838. The cooling lumen is 836, and the antenna catheter/guide wirelumen is 844.

This concept combines the shared guidewire and coaxial cable lumenconcept in DNX-001 with the cooling fluid holes in the balloon tapers asin DNX-008 B, C & D. The shaft of the treatment catheter requires onlytwo lumens. One lumen is a shared lumen for guidewire and coaxial cableand the second lumen is for inflow of cooling fluid. The lumenconfiguration can be either a simple coaxial design or multilumenextrusion.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1. A cooled microwave denervation catheter comprising: a catheter bodyhaving at least one fluid passage and an interior lumen therein, theinterior lumen having a first portion in a first axial region, a secondportion in a second axial region, and a taper between the first portionand the second portion, the second portion having a smaller diameterthan the first portion; a balloon in communication with the at least onefluid passage to receive cooling fluid for inflating the balloon into ashape that surrounds the catheter body at the first portion of theinterior lumen, the cooling fluid having a temperature that is less thanbasal body temperature; a microwave antenna catheter configured to beinserted into the interior lumen of the catheter body, the microwaveantenna catheter including a coaxial cable and a microwave antennaconnectable to a microwave generator to supply power to the microwaveantenna to cause microwave energy to be emitted from the microwaveantenna, wherein a distal end of the microwave antenna catheter isconfigured to engage the taper between the first portion and the secondportion of the catheter body upon insertion into the interior lumen,thereby positioning the microwave antenna in the first portion of theinterior lumen.